Sampling events

You can enable event sampling to reduce the number of events sent to Honeybadger. This is especially useful if you are hitting your daily event quota limit:

config :honeybadger,
  # Sample 50% of events
  insights_sample_rate: 50

The insights_sample_rate option accepts a whole percentage value between 0 and 100, where 0 means no events will be sent and 100 means all events will be sent. The default is no sampling (100%).

Events are sampled by hashing the request_id if available in the event payload, otherwise random sampling is used. This deterministic approach ensures that related events from the same request are consistently sampled together.

Per-event sampling

The sample rate is applied to all events sent to Honeybadger Insights, including automatic instrumentation events. You can also set the sample rate per event by adding the sample_rate key to the event metadata map:

Honeybadger.event("user_created", %{
  user_id: user.id,
  _hb: %{sample_rate: 100}
})

The event sample rate can also be set within the event_context/1 function. This can be handy if you want to set an overall sample rate for a process or ensure that specific instrumented events get sent:

# Set a higher sampling rate for this entire process
Honeybadger.event_context(%{_hb: %{sample_rate: 100}})

# Now all events from this process, including automatic instrumentation,
# will use the 100% sample rate
Ecto.Repo.insert!(%MyApp.User{}) # This instrumented event will be sent

Remember that context is process-bound and applies to all events sent from the same process after the event_context/1 call, until it’s changed or the process terminates.

When setting sample rates below the global setting, be aware that this affects how events with the same request_id are sampled. Since sampling is deterministic based on the request_id hash, all events sharing the same request_id will either all be sampled or all be skipped together. This ensures consistency across related events.

With that in mind, it’s recommended to default to the global sample rate and use per-event sampling for specific cases where you want to ensure events are sent regardless of the global setting, or you are setting the sample rate in the context where all events with the same request_id will also share the same sampling rate.